"On behalf of the people of Uganda I am challenging you to free and fair elections," said Wine, making his bid in front of his followers.
Wine, whose real name is Kyagulanyi Ssentamu, told Associated Press newswire last week that he was running, but also concerned for his own safety.
Wine fled the country in 2018 after he was brutally attacked by security officials. He has accused Ugandan security forces of torture.
Ugandan police have charged Wine with treason, saying he incited supporters to throw stones at the presidential convoy during a campaign event. He is also charged with annoying the president and disobeying authority. He denies all charges.
The 37-year-old charismatic singer leads his “People Power” movement that attracts youth voters who are frustrated with high unemployment and lack of opportunity.
"President Museveni and his praise singers dismissed us as inconsequential. The people of Uganda ... continue to prove them wrong," he said.
Police continually block Wine’s efforts to hold rallies or concerts, claiming that they are working to maintain order, as Museveni has accused Wine followers of rioting.
If the singer is convicted of these charges, he will be unable to run with a criminal record.
Museveni, 74, has been selected by his party to run in the 2021 elections. He eliminated the age clause from the constitution, allowing his to run after age 74.